The quickest iOS foursquare Client in the old west
The App aims to essentially combine foursquare with Amazon 1-Click, you tap on a venue and BAM, you're checked in. I kept finding that after visiting a place I always ended up stalling friends with conversation while checking in because foursquare takes several taps to check in. It even spawns a background task so you can close it the second you attempt to check in.
NOTE: There are several #warnings in the App for foursquare OAuth and Flurry keys that I stripped from the App. In order for it to function as normal you'll need to provide these keys.