Of course, it doesn't hurt that it came out in 1997 and I've had a copy living in whatever bag I have on me since 2006. :D it's had a good six, seven years for me to have fun with it before Love Letter came along.
(In case you're wondering, the reason that it's Pico _2_ is that Pico was published in 1996, made out of excess cards from another Doris & Frank game. Pico 2 is a revision with a more balanced card distribution)
Pico 2 is a streamlined and more refined version of the old card game GOPS. It consists of just eleven cards, four to thirteen, plus sixteen. Every card has a set of pips on it, ranging from one pip on the four to four on the sixteen.
You deal out five cards to each player and set the last card face up, so you both know exactly what's in each other's hand. On each turn, you each secretly pick out a card and then simultaneously reveal them.
The high card wins UNLESS it is more than double the value of the low card. In that case, the low card wins. So the five will lose to six, seven, eight, nine, and ten but beat eleven on up. Whoever won that turn puts their own card face up in front of them in their scoring pile.
The round ends when someone is down to one card. You count up the pips in your scoring pile. THEN (and this is the really clever bit), you trade hands and do the whole thing over again. Highest cumulative score wins.
A game of Pico 2 honestly takes only about five minutes. If it took a half hour, that would be way to long and get tedious. But, for five minutes, it offers a lot of interesting bluffing and second guessing. I've played it with a lot of different people and it's always been a hit.
Part of what makes it so engaging is that it's so simple but it's also downright elegant. It takes the older game of GOPS and makes much tighter, honing the decisions down to a razor's edge. It packs a lot of tough decisions into five minutes with eleven cards.
A lot of tiny games have spent time in my pocket or game bag, ready to be played at the drop of a hat at restaurants or bars or coffee shops. Pico 2 is the one that has never stopped being part of my traveling bag of tricks. Yes, it takes up almost no space but it also is such an easy game to teach while still being challenging and fun.
Some micro games are like dancing bears. It isn't that the dancing is good but the fact that the bear can dance at all. Pico 2 is not a dancing bear. The trick isn't that it is only eleven cards. The trick is that it's a good game.