While bored in middle school algebra, I figured out on my TI-30 which number, raised to itself as a power, would equal 9.9999999E99 (not sure on the precise number of nines after the decimal point, but basically it flooded the screen with all nines).

56.96124843225 ^ 56.96124843225

Wolfram confirms that it's pretty close to a full googol. Of course, you can keep adding digits to the end of the number to make it even more precise. Maybe I'll write a script to do that.