Watch the O'Donnell-Coons race, and the McMahon-Blumenthal contest. If either of these goes to the Republican candidate, it will be Game Over for the Dems.
Early reporting shows that the Coons camp is trying to spur on a lethargic electorate, and that turnout in New Castle is well below the mark that would ensure his victory.
The McMahon race was tightening up over the weekend, and it looks like the poll models are over-representing Democratic enthusiasm (and participation levels). Rossi-Murray will come down to lawsuits, and the Fiorina-Boxer race will likely be won by Senator Ma'am (but it will be close).
In the House, watch Sanchez-Tran (CA-47). This one has been flying under the radar for a while now and it looks like Tran may pull it out. If he does, it will be one that the Dems weren't expecting to lose and it may add to the "super-wave" that is beginning to crest.
Buckle in, it is going to be a long night.