Doing a little digging from the Reddit link that Heavenfall posted, I found this site: http://steamdb.info/sales/
Using the filters 'Games' and 'US Dollars', I am able to sift through the deals that didn't happen to make the front page. They start off with the 90% discount sales, so you might find that little indie gem that you have been looking for.
Thanks for pointing me in the right direction Heavenfall.
PS-I don't think Amazon will match Steam's flash sales. I was hoping to get Civ V's Brave New World for a 33%+15% discount (it is 33% off as a flash sale at the time of this post), but it was the regular $30 on Amazon.