Repair broken filesystem on Ubuntu

I recently encountered a problem with my laptop running Ubuntu 11.04. Grub got corrupted and apperently the file system too. All I got when booting was a Busybox shell. Luckily I came across this solution.

1. Boot a Ubuntu Live cd (or in my case a USB stick, created with Unetbootin) 
2. Run chfsk -v /dev/sdx (where sdx is your broken partition) 
3. Just answer yes on all the questions that comes up, and reboot! It fixed my problem.