One patron can sip espresso and study for a trig midterm on a couch in the back while another talks loudly, sipping a glass of vino at the bar in the front, and never the two shall meet. That's because Leela European Cafe -- open 24 hours a day -- is as panoptic as the European continent itself, with lofty ceilings and a wall of windows facing the street. Serving a full menu, with free WiFi and a large stage and dance floor, Leela wants to be everything to everyone -- including that indecorous creature of the night, the chain-smoking teenager. There's a vending machine that sells cigs and a ventilation system that sucks smoke like the lungs of a Sicilian. At Leela, teens can assimilate into the cafe culture and learn to be buzzed all night, just like adults.

There isn't a big market for cheese fries and softcore porn, but Tom's Diner has it cornered. A nightly 3 a.m. destination for hopped-up club-goers and insomniacs, the friendly restaurant is outfitted with a number of Touch Maxx games, heaven-sent by the touch-screen mini-arcade bar gods. The black idiot boxes rest on the edge of yellow-upholstered booths and provide at least five to ten minutes of greasy-fingered fun between coffee refills. There's music trivia and word scramble, but the erotic photo hunt is by far the best T&A that 25 cents can buy. You choose babes or hunks, and Touch Maxx will give you a Highlights-like X-rated game of "Can you find the differences between these two nearly identical pornographic photos?" The winner is rewarded with a priceless flash animation of jiggling body parts.

That St. Mark's Coffeehouse is a great place to stop for a cup of joe should not come as a surprise to anyone. This offshoot of the original LoDo spot has drawn the hiptelligentsia since first opening its enormous sliding garage door in 1997. They come for the coffee, bagels, panini and sweets, but stay for the company: cool teachers grading papers, the students who wrote them, artists and journalers, businessmen and housewives, and, of course, those insufferable coffee-shop rats, smoking hand-rolled cigarettes and reveling in their own asinine chatter. St. Mark's has always been a good coffeehouse, but it's gotten even better over the past year. It ditched the fee for wireless and opened up the Ubisububi Room, a performance area that shares basement space with the Thin Man next door and offers everything from free movies to standup comedy to live acoustic music. The Thin Man and St. Mark's share ownership as well, and a swinging-door relationship allows 21-and-up patrons to enjoy a cocktail on either side of the common wall. So grab a mocha or a mojito, and settle in to enjoy the Paris of the Plains version of cafe culture.