Alphametics + Cryptarithms - Try this: SITES + NONSENSE + NONSENSE + NONSENSE + POINTED = POINTLESS. Where each letter is a number from zero to nine (solvable!)
ROLLOVER App - It's what we've been up to here at Pointless Towers for the last 18 months - Rollover is quirky and for the iPhone, iPod touch and iPad :o)