One large interest I have is competitive programming. I find it very fun to challenge myself by solving algorithmic problems under time pressure.

Here is a list of yearly programming competitions open to everyone. Some consists of multiple competitions like qualifiers and finals. In those cases the start month is the month of the first qualifier.

Name Start Month Type Tags
Google Hash Code February Optimization team
Google Kickstart March Algorithms beginner
Google Code Jam April Algorithms
Facebook Hacker Cup June Algorithms
Codingcup September Algorithms sweden
Nordic Collegiate Programming Contest October Algorithms team , nordic
SnackDown October Algorithms team
Advent of Code December Misc beginner

For a very up to date list of upcoming competitions, including almost everything, visit https://clist.by/.

One becomes a lot better by practicing. If you are very new to this I suggest you go to open.kattis.com, and start solving some problems ordered by difficulty.

Most competitions are quite friendly to beginners, starting with solvable problems for newcomers, but some are extra friendly, which I have marked with the beginner-tag in the table above.

Resources

Also, there are a lot of resources online where you can practice. Some also hosts weekly or even hourly competitions, where you can test your skills.

Hall of fame:

These contests are discontinued, but I enjoyed them very much when they still existed. I hope some of them will come back!