Two week old yeast cake?

I racked a batch to my secondary about 2 weeks ago and covered over the primary with plastic wrap. I went on vacation and haven't had a chance to brew yet. My basement is about 55F in the winter. Would this yeast be okay to use again? It still smells fine.

Well, in Norway they used to brew beer using yeast that they dried on boughs of juniper that had been left at the bottom of the fermentor... So theoretically at least, I would say that there's probably no problem at all.
Would I ever do it personally? No, probably not... I mean, having to buy more yeast sucks, but one packet only costs $2-6, so why risk an entire batch of beer?
But if you are into doing some experimental brewing....

With yeast, if it smells ok, it is ok. When autolysis starts, it will be painfully obvious.

I bottled my yeast/trub/bottom of the primary beer remnants about 3 weeks ago. Just got around to washing the yeast today - dumped the bottles into taller straight walled vessels, etc, none if it smelled bad, I pretty much trust it. Just got the starter going will know tomorrow if it's actually fermenting at all. Also put some into a vial for future use. The bottles weren't refrigerated these past weeks, they just sat in basement in low 50's.
Good luck, let me know how yours turns out, I'll report back on mine.

Ive experienced autolysis once with a lager kit (one of my very first brews). I had left it for about three weeks and the gravity was about 1010 and i was slavisly waiting for it got get down to 1004 (thats what the kit said, i now know that the extra body was due to the fact that i'd used two kits and not went with the 1kg of sugar rubbish ). After reading up some stuff on the web i shook the absolute bejaysus out of it for 10 mins all i managed to do way to wake up some hungry yeast and turn them into cannibals. I turned what had been a decent brew (samples for gravity readings) into what smelled like melted down car tyres (really overpowering). I never did manage to get rid of that smell from that fermenting bucket and i ended up using it for a general bucket almost two years on it has finally lost that horrible 'burnt rubber' smell.

B4B: From what Palmer says, you'll definitely know the difference. Normal healthy yeast sludge doesn't usually smell all that great, but it's not "blech!" nastified. When autolysis sets in, he says it is so bad that it may make you gag. Like a bushel of really rotten eggs. I'll take his word for it, and try not to recreate it on my own.

I dumped a 4" cake of Pacman yesterday. I too had been saving it in a sealed carboy for 2 weeks, too damned lazy to clean it and put it into jars. Plus, I had fermented my Burninator barleywine with it, which was made with star anise...and that star anise leeches into everything, including the cake. Plus, I had already gotten like 4 brews out of the Pacman, so...what the hell. Probably started mutating by now anyway.

Update -- my starter began showing activity in about 4 hours or so, but it was very slight. By then my batch of beer was ready to pitch -- the starter had a LOT of yeast in it since it was washed yeast from the previous batch, I just did the starter to be sure the yeast was viable. Anyway, I pitched the yeast Sunday night, and mid-afternoon monday my batch of hefe was foaming out the blow tube! Slowing down already (tues AM), but it's still working, I expect this to be done by Saturday, may let it settle out a few extra days before kegging or may go straight into keg as secondary. Worked out fine, I'm guessing yours will too, mmditter. Let us know how you make out.