Oh dear GOD yes. I remember writing something and I couldn't, for the life of me, remember how to write the kanji for "machine", at all ... I made all these pointless random strokes in hopes that it'd come to be, but it didn't until I came home and poured through my kanji dictionary. ;_;

And I've had conversations in Spanish where I've had to use, "esa cosa que se usa para ...," simply because I've completely blanked on a rediculously simple word.