The idea of an open convention–and an opening for Gore–is not so far-fetched for a few reasons.

1. Unlike the general election, whereby a candidate wins all of California’s electoral votes if he or she wins by a single vote, the Democrats allocate delegates to the national convention proportionally. So, if Hillary or Barack win 40% of the vote in primary after primary, they won’t win a majority of delegates, and it’s the candidate with a majority who wins the nomination, not the candidate with the most delegates. 
2. With Super Tuesday’s 22 states coming up and with Obama gaining some momentum from his shocking win (the margin not the mere victory) in South Carolina, it may be that he can cut the gap a bit further in the state-by-state polls and score some mild upsets on February 5. Given that Obama is likely to trounce Hillary in his home state of Illinois, that Clinton may not defeat Obama by as much in New York, with California looking like a tight contest, Obama’s strength among African Americans in the south, and the potential for Edwards to pick off some votes in the south, it’s all a recipe for nobody to emerge from Super Tuesday with much of a lead to claim a lock on the nomination.
3. Obama and Clinton both have the money to go the distance and afford a campaign after February 5, unlike those on the Republican side such as Huckabee and Giuliani, for whom defeats come at the price of financial viability. If you can’t spend, you can’t run.