110th Special Elections

[Verily]

We have three open seats. It's looking likely that we'll get at least two more soon (Renzi and Doolittle) from resignations. A few other congressmen (Young and LoBiondo) have begun to be embroiled in Abramoffgate and may be forced to retire if things get worse for them. If Jindal is elected governor in Louisiana, that will trigger another special election. That's 8 special elections.

Then there is always the potential for deaths or unforeseen scandals and subsequent resignations. It is highly unlikely that anyone from Congress will consent to being appointed into Bush's cabinet, but there could be more people seeking university appointments or state offices as Meehan has.

None of the current open seats are in serious danger. The Democrats would stand a chance at Renzi's seat and LoBiondo's (which would easily be the most endangered seat up in a special election for a long time), and maybe at Doolittle's. Young is harder to say since Alaska is not particularly partisan.

[Verily]

I just found another instance in which we could be seeing a special election.  Two representatives from Pennsylvania are competing to be the Democratic nominee for the Philadelphia mayoral race.

According to Wikipedia, though, neither is likely to win the nomination. Both PA-01 and PA-02 are safe seats for the Democrats.