Wolfram Alpha

1
http://www.wolframalpha.com

it's a neat mathematical and computational search engine. pretty fun to play around with. for example, go to their home page and enter the following search query:

Code: Select all

PolarPlot[(1+sin(t))*(1+0.9*cos(8t))*(1+0.1*cos(24t))*(0.9+0.05*cos(200t)), {t,-Pi,Pi}]
some people have way, Way, WAAAAAAAAAY too much time on their hands.