Code Wars www.codewars.com
Some of the solutions. Currently Kyu 5 and above.
Directory of Projects
adamandeve adamandeve buildingblocks converttimetostring describealist dontgivemefive doublecola englishbeggers enoughisenough fibonaccilastdigit findcountmostelementinarray findsmallestinteger findtheoddint highestandlowest highestscoringword interactivedictionary jadencasing johnandanncodewars multiplesof3and5 mumbling myheadinwrongend nicknamegenerator nthseries onesandzeros paginationhelper parseniceint regexp/isdigit removeduplicates reversedstrings reversedwords scramblies sentencesmash sequencesum stopspinningmysword sumofoddnumbers twofightersonewinner vowelcount yourorderplease