My recent animation experience has taught me that I need every scrap of CPU time I can get my hands on, and it needs to be MIPS-based (it has to do with the different ways different CPU vendors do floating-point calculations--believe me, there is a reason there are no mixed-cpu render farms, where some CPUs are Intel, some are IBM/Motorola, and some are Sun SPARC--those differences can add up to peculiar flicker in procedural textures ).
So even as I relax this weekend, I am taking my Origin 200 server, Gondwanaland apart from the state of storage it's essentially been in for the past two or three years. At this point, I have no idea whether it will even power on. But I can't say no to 4x180 MHz R10000s. This system is positively ancient, certainly no more recent than 1997.
But it is still useful.
Additional adds: an R4400 Indigo2 (Carcharodon), another Octane and possibly an R5000-based Indy. If my living situation were different, I'm certain the electricity costs alone would not be worthwhile. But it might be interesting to see if systems from 1994 can still be used in this environment.
If I'm successful, I may write about the composition of the network later.