I collected the yeast and stored it in the fridge in sanitized White Labs tubes. The yeast has been sitting in my fridge ever since and I noticed it was starting to turn more of a darker beige rather than the light tan normally associated with healthy yeast. I'm guessing this is due to the fact that the yeast is getting older. I remember a Basic Brewing podcast in which James Spencer was able to nurse an old yeast sample back to life. If I remember correctly, it was about a year or more old and his LHBS gave it to him for free. So I decided to give it a try and use my recently constructed stir plate to try to resurrect this strain.
I made a simple wort as described in John Palmer's how to brew. I pitched the yeast about 30 minutes ago, so time will tell if I'm able to bring this yeast back to life.
Update 5/26/2009: I haven't had time to brew a batch yet, but it seems as though I was able to nurse the Fat Tire yeast back to health. I added one White Labs sized sample of yeast and after a few days was able to harvest four+ samples. They probably have about 2/3 volume of a typical White Labs sample, so they'd benefit from a starter a few days before brew day. I'm going to try to brew a batch of my Microbus Amber this weekend. I'll post the results (hopefully good) as soon as I have them. I'm interested to see how stable this yeast is or if it will mutate after a few batches. My sample had a really nice bread/biscuit aroma, so hopefully that's a good sign.
Update 6/29/2009: I never did get around to brewing this batch but I saved the yeast yet again. So this one is still in limbo.