I remember someone posting about physics mnemonics, and I found a few I thought were cute that might help us to be human calculators on the PGRE:

For square roots remember the following phrases. The answer is in the number of letters in each word in the first half of the quip - so for square root of two, I =1 wish=4 I = 1 knew =4 --> 1.414, and so on.

I wish I knew - the root of two

O charmed was he - to know root three

So now we strive - to find root five

and for Pi's reciprocal:

Can I remember the reciprocal?

Count 'em up, and put a 0. in front to get the reciprocal of Pi.

I've got to go now, in the next three weeks I have the PGRE, the general GRE, 4 midterms, NSF fellowship proposal and a thesis proposal due... I just might not make it to Thanksgiving...