I recently discovered and purchased a new game called Time Barons. (
http://www.time-barons.com/) It's a great game and it only takes about 15-20 minutes. I got it a week ago and it's already seen about 15 plays.
I highly suggest you take a look at this game. Here's a quick rundown on the pros and cons:
+Very fast play
+Simple rules
+The co-designer John Perry is active on BGG and will quickly respond to your comments
+It's only $20 for the full game, and shipping is about $4. I'd suggest getting the cards only which is the low, low price of $10
-Only 2 players. If you want to play with 4 you'll need an extra set.
-The art is a little cartoony. I personally love it but it might annoy some people.