I want to invite you to participate in HackerEarth June Clash '15. It is 24h-long contest, scheduled on June, 20 (check your timezone). Problemset consists of 4 algorithmic tasks of varying difficulty with partial solutions allowed - you get points for every test that you solution passed, and one approximate problem - your score for this task depends on how good your solution is comparing to current best solution.
Problemset was prepared by Pavel Sheftelevich - you may already know him for preparing some interesting problems for CodeChef contests, he was an author of January Lunchtime 2015, and also an author of April Clash and co-author of May Clash. I was co-working with him as a tester.
There will be nice prizes for toppers:
Amazon Gift Cards for top3 ($100 - 80 - 50)
HackerEarth T-shirts for top5.