I was running some numbers on MyDD today and I really saw how close we are to the end game. Even if you give Clinton some rather favorable assumptions, Obama only needs 40 of the unpledged non-add on superdelegates to endorse him.
The reality is probably 30-35 will be enough, but I think that 40 will clinch. Someone correct my math if I'm off somewhere.
According to the New York Times, there are 689 remaining pledged delegates. (This statement is where my math went wrong. Stupid NY Times. See correction below.) Let's suppose that Obama gets 45% of them. With NC, OR, SD, and MT in the mix - not to mention the fact that when people look at the details district by district, it's very hard to build up a larger lead than that, even with 15-20 point leads - that seems pretty favorable to Clinton. That's 310 more delegates.
Also, let's assume the add ons break 50-50. I actually expect Obama to win 3-4 more of them at least based on the state by state breakdowns, but we'll be generous and give Clinton more of a benefit of the doubt. That's 35 more for Obama; I rounded up to make up the difference.
DemComWatch has Obama at 1640 after today's endorsement. 1640 + 310 + 35 = 1985. The magic number is 2025. So even with conservative assumptions for Obama, he just needs 40 more people to win even if everything breaks Clinton's way. Start the countdown with every endorsement.
UPDATE: Errr, nevermind. See the comment below. It looks like the NY Times lumps together pledged, add ons, and superdelegates from a state so I was adding the same delegates multiple times. Things are still really good, but not that good.