I have found that the creepiest apps are the best.
Some of the things I thought may be good have turned out to be buggy / shitty. Lets take imaze for example

Anyway - after playing thru a bunch of 'free' apps, this is what I have walked away with.
- AOL IM: finally
- Graffitio: Its an odd app the lets you create an anonymous discussion thread with time-stamps at various geographic positions. For example: you may go to a favored restaurant and discover a rare disappointing item on the menu. You can leave a posted message associated with that geographic location in the restaurant so that others can be warned and comment. I have found that I like tagging it up and commenting on everything while waiting in a line etc...its so matrix

leaving text data at a location that can only be read by another graffitio user in the same location. Make sure you check it out when you go everywhere as I have already found VERY funny anon comments in places.
- iFob: A chat/share app that lets you see other ifob users in your local range. So far I have not encountered another ifob user - it is seeming like it will show same LAN users only. May be deleted soon

- Remote: FINALLY - I can use my iphone to remote control itunes running on my macs and therefore play music in any room of my flat whenever i feel like it using my phone as the controller. Its the real apple app.
- Zintin: A random user proximity chat tool that seems to work way better than ifob. Everyone is on zintin and you can post pictures on your own wall or on other users walls that are within your local range. This seems to use your IP address and cell tower location like google maps to determine what other zintin users are local so its like 40 people every time i take a look at the thing.. THERE ARE FUCKING FREAKS ON ZINTIN. People are of course right away posting photos on each others walls like tit shots and shyt - its chaos.
What do you have? I haven't tried any titles that you gotta pay for yet. Monkey Ball looks cool - as does Bomberman. I may get those.