The Gridulator by Stuntbox, a cool utility for quickly making design grids:

“Tell Gridulator your layout width and the number of columns you want, and it’ll spit back all the possible grids that have nice, round integers. Just the thing for pixel-based designfolk.”

….And a lighthearted alternative to fussy grid-making:

“The 997 Grid System—makin’ sh*t bigger and simpler…”