Check out this baby! It's a 450VA UPS Power Protection Unit with a 4 way extension leadfor less than £15 - yes, you read right, about a tenth of an average UPS.

I've ordered two, one for each PC because the electrics are a little unpredictable here.
I should get them mid-week and then I can laugh at the next brownout!

You can pick them up at eBuyer.