So here's a rumor I'm going to float, and before I reveal the source, hear me out: Vice-President Joe Biden, who's all but expected to throw his hat in the ring for the Democratic presidential nomination and mess everything up for Hillary, may be coming to San Francisco to make the big announcement. A big, mysterious event appears to be taking shape at Bill Graham Civic Auditorium for Labor Day weekend and the week after and no officially announced events are on the books, as far as anyone knows. As Hoodline reports, documents filed with the Planning Department only say that a "trade show" is taking place, possibly from September 4 to September 10.

A few people leap on the fact that Apple tends to do product announcement events right after Labor Day, but they tend to stick to the Moscone Center for those — or there was last September's big Apple Watch announcement which they did in Cupertino.

But it's a commenter on Hoodline who throws out the possibility of this being a Biden thing, saying "I understand Biden loves San Francisco" and noting that all the security that's been observed surrounding the auditorium for several days doesn't really seem befitting of a trade show.

It would seem more likely for Biden to pick a place like his hometown of Scranton, Pennsylvania to make a big announcement, since Pennsylvania's always a battleground state, or to do it in Delaware, the state he represented as senator. But perhaps the draw of tech wealth donations and the possibility of stealing some of Hillary's Left Coast base are big enough advantages for Biden to begin his campaign here.

Also, as The Wrap reports, Biden "invited several major Democratic fundraisers to meet with him the week after Labor Day at his official residence at the U.S. Naval Observatory in Washington, D.C."

As of today, the President has given his "blessing" to Biden for any possible presidential bid, as the NY Daily News and others report.

Will Biden come tapping the liberal tech well right out of the gate, following in the footsteps of Obama and taking a different tactic than Hillary, who's already been campaigning for four months in the Midwest, Florida, and Texas?

Stay tuned.