It started with a couple of images of Lucky Star done up as Gurren Lagann (one of the mid-episode eyecatches and one a parody of the main TTGL poster), and eventually it led to me finding a bunch of really awesome Gurren Lagann crossovers. Good times. Check 'em out! And as always, if you have a name to credit an image that I don't have, please please please gimme!
1) Credit needed.