Texas, for example. Did you forget that the former seat of Tom DeLay (Texas-22) is widely expected to be won by a Democrat? DeLay resigned from the seat, and the state GOP was blocked by a court ruling from replacing DeLay's name on the ballot with that of another Republican.
RealClearPolitics.com summarized the election in Texas-22 thusly:
This is the sort of condition we need to have to see a district as conservative as TX 22 go to the Democrats: either the Republican has to be under indictment or there has to be no Republican on the ballot.
... As the saying goes – you can’t beat somebody with nobody. Technically, the Republicans have nobody. But the local GOP has managed to coalesce around their “nominee” – Houston City Councilwoman Shelly Sekula-Gibbs. She is their write-in choice for the seat.
The obvious question: how will enough voters manage to write-in a candidate whose name has six syllables and a hyphen?