Due to highly poor internet conditions in my university, we often encounter google error pages. But this happened during my winter break when googling some stuff, I was redirected to a Google 500 error page. What caught my attention was that arguments were present there but the page was a html page. So I thought of viewing the source and I saw that, just some regex matching using javascript was done to extract those parameters. The parameters were being passed as a link in the page. I tried XSS and it worked out. The awkward thing was that they never tried to filter the url, when the request was being sent to their server. Then I reported it to Google. May be they were in their winter break, so they took some time to respond. But atlast they responded and google rewarded me with $1337.

XSS in Google