A Taylor expansion of the function you want to look at will let you calculate it to arbitrary precision by taking enough terms. Then you just need to be able to add and multiply (and either a computer, or a lot of time!).
I prefer the nondetermanistic "many worlds" approach:
1. I write down random digits, hoping they're correct.
2. If they're wrong, the universe is destroyed.
We continue to exist only in those universes where I write the correct results.
This approach is especially effective for constants like Chaitlin's [tex]\Omega[/tex] where there's no easy way to calculate it. Of course, I haven't actually managed to implement step 2 yet. Research continues (see the IEDAB's methods for destroying the Earth for the foremost research).