From Wikipedia: Oblique Strategies (subtitled Over One Hundred Worthwhile Dilemmas) is a card-based method for promoting creativity jointly created by musician/artist Brian Eno and multimedia artist Peter Schmidt, first published in 1975. Physically, it takes the form of a deck of 7-by-9-centimetre (2.8 in × 3.5 in) printed cards in a black box. Each card offers a challenging constraint intended to help artists (particularly musicians) break creative blocks by encouraging lateral thinking.

This is a web page that randomly picks one of the oblique strategies and shows it to you.