Metro announced that they are running a rush-hour schedule for virtually the entire day....

Biking in makes sense, but I would suggest that depending on where you live, try parking 10 miles away and then riding closer. Have shoes that you would be comfortable walking in, and bring enough layers that you will be warm just standing around for a while.

If they are right about the number of people, there will probably be *tons* of people walking all over the place. Sidewalks and trails are going to be full, and as you get closer you would end up riding in the street.

The thing that resembles this the closest is July the 4th, I guess. But that is in the summer and people would be comfortable hanging around all day. If you work downtown and have a building pass of some sort, bring it with you so you have a place to go in and warm up.