fun programming challenges

[TheBean]

I learnt how to program in java a while back in high school. but its been some time and I've kind of forgotten how to do stuff. is there any place I can go to do some programming challenges so I can get back in the rythm of programming?

[colonel_mortis]

Project Euler has good mathematical-based programming challenges, which are definitely worth a go if that's the sort of thing you're looking for - https://projecteuler.net/

[geo3]

Google foobar is another one. But you either need to stumble into it or be given an invite by someone who has gotten an invite link by completing some of the challenges.