These are some quick and dirty Redis tests I did using Java and Jedis.
Did it mainly to learn Redis usage and to do some unscientific performance tests.

Tests require you have a redis running locally on the machine using the default port.
Check out http://redis.io/download for installation tips.
The easiest solution is to use some package manager. E.g. "sudo port install redis" and then starting it with "redis-server"

To see what use cases Redis is good for, read: 
http://highscalability.com/blog/2011/7/6/11-common-web-use-cases-solved-in-redis.html