This might be my first one...
During the last 3 months or so, I have seen a few of my stocks be up 40- 50-60-70% in a single day (CNO, MNI, WNC, CVGI, GTN, HLCS, KERX, INHX), and today I might have my first 100%-one-day-jumper in my portfolio: RPRX.
I bought 1,000 shares of RPRX at $0.89 on 10/1/09, just to see it jump 103% today (it was up 130% this morning).
I know there is 2 more hours left of trading, but I'm hopeful RPRX will stay above the 100% mark.
Some of my stocks and my buys mentioned above can be seen in this post and its comments.