I've cheated a few times, and bottled the yeast cake into several bombers, then stored them in the beer fridge. You'll often end up with highly carbonated yeast that way, so watch out for gushers when you open the bottles.
My last brewday, I cracked open a five month old bottle of Pacman yeastcake, washed it in a growler, and pitched the washed yeast directly into a 2l starter on the stirplate. Two days later, I crash cooled, decanted, and pitched a nice batch of yeast. The cream ale I pitched it in was fermenting merrily the next morning.
It's probably not a good idea to do this for too long with an individual strain of yeast, though, as I'm sure it's stressful to the yeast. Nevertheless, it worked. YMMV and all that.