Garden has an unusual seasonal calendar. It has no day time, but the city itself as well of the surrounding forests are kept relatively warm by some sort of cosmic radiation or unseen energy force coming up from beneath the ground. Most of the year it hovers around the same temperature, a bleak below room temperature that necessitates a jacket or long sleeve, especially in the winter. But it isn't too uncomfortable for the denizens of the city. However during a short few months of the year, Garden is colder then normal. Snow begins to fall and the town is hobbled up indoors. On the opposite side of the calendar year, there is a summer rainy season that makes the city much warmer and more humid.
During the cold season, human immigrants to the city began to set up their own celebrations for Christmas. Only to find the other aliens quickly doing so as well. For some strange reason, every alien race asked had a Christmas style tradition; the secular Christmas, not the religious one. All of them had reasons, and were naturally shocked to find other species in the nightlight city sharing the same symbolism. Every culture in Garden seems to come from planets and worlds with a Christmas analogue, or perhaps it is some kind of infectious psychic idea that warps their own traditions. The squid people of Rambulon have vivid memories of waiting to see a squid crawling up their vent shaft dressed in a red and white outfit, baring gifts. The scavenging carnivore birds of another dimension specifically have recipes for baking cadavers into little crispy cookies to leave out with a glass filled with blood for “Santa” to drink on his journey. The details differ, some cultures replace the “elves” with inferior caste members of their worlds or prefer to make gifts as unappealing as possible to ward away mischievous spirits, but for the most part everyone likes Christmas.
If you dislike this concept; then just make human immigrants to Garden City still celebrate Christmas and everyone caught on and does it too. That could be the “humans” special thing as a race in this setting.
20 Garden Christmas Gifts
 Untouched plasma TV screen! Still wrapped in its offworld plastic. The TV is “plasma” in that it actually contains plasma in a chamber along the top, glowing in any dark room with energy pulses. Might cause a blackout or two during setup from needing all that energy. There is no TV network in Garden but you might be able to get a film or a talkie on there.
 Fortune Telling coupon; one free actual psychic reading. 84% accuracy.
 Hovercar Waxing.
 Lovely fruit basket. It's from a Random Gang, which is the only special thing about it.
 Gun cleaning kit. Or just a whole gun, which is a nice mid-level present for most folks.
 Year-long pass to board the skytrams around Garden's busiest area. By far the most useful present you will ever get.
 Dinner reservations for two at The Bronzer, Garden's most premiere restaurant and lounge. Classy Jazz & Swing music, great offworld drinks, tons of the rich and famous. If you don't go, a mob boss will hire a hit on you for wasting your reservation since it's so exclusive and they get jealous.
 Extremely expensive bottle of bubbly champagne that can help grant wishes. Usually reserved for New Years eve parties.
 The secret location and phone number of Cloreese's Massage Parlor. Her rates are affordable but she has a very strict list of clientele. She offers a soul alignment. You'll come back a changed man; your body and psychic energies perfectly entwined. Effects last 2d4 months or until you do something morally repulsive or very, very petty.
 Some kind of pedigree off world pet. It's orange with blue rings around its eyes, bit of a dog mixed with a kangaroo with some weird alien tail and extra spines along its back and ribs. Has a difficult diet and hard to train, but if properly cared for could fight for you as well as a professional kickboxer.
 Mundane item like a lamp, flashlight, empty violin case, or an ID card for someone you don't know, etc. The item is from an underground storage locker and has a unique power.
 A “Are you a Psychic?” book. It's a cheap, overpriced pulpy piece of shit. Actually has 1 in 20 chance to reveal unknown psychic potential.
 Full set of backpacking gear, tent, and high boots. Suitable for exploration of the forest outside of Garden city. Common gag gift, nobody would dare go on a hike in the dark woods.
 It's a double sided record containing the best Jazz singles of the year.
 Automated bill counter. Put through a machine, counts up the glow in the dark bills and bundles them into nice stacks.
 Wrapped up box of cigars, made of Garden's finest midnight black grass.
 Single box of chocolates from off world- your world in particular. Is a little old, but still a nostalgic luxury too good for most to pass up.
 Bolt of wisp cloth. Comes only from one planet offworld, only rarely imported in such large and useful quantities. Pinkish but color changes depending on the light. Extremely comfortable and delicate, used to make bedsheets, pillowcases, robes, etc. You'll have to take it to a tailor to get it made into something useful.
 Full bottle of sweet malt liquor. Brand is Fourth Eye, displaying an alien face with an extra eye from its normal three.
 Commemorative coin for the city's tricentennial birthday, which also grants special access to the city's secret rulers club for that night only. That's two years from now, you have no idea who sent this gift to you.