I've been looking forward to the grand prix since news broke of it two years ago.  It should be a great time.

I haven't seen an unusual glut of ads for visiting girls this weekend.  Not sure Indycar moves the needle enough to draw the providers in the way a Super Bowl, etc., does, but racing does draw pretty civy girls from around the world.  There certainly will be plenty of corporate types who like to hobby visiting this weekend.

Don't expect the economic impact to be very strong.  The economic impact of sporting events is way overblown.  Figures of "the impact on the local economy" mostly state the gross income of the owners/promoters/etc.  From what I understand, Labor Day weekend has traditionally been slow in Baltimore, so the hotels, restaurants, etc. will do better than usual, but most of that capital flows out from the city pretty quickly.

I do believe, however, that Baltimore was able to secure Federal funds to pay for the repaving.  That's probably going to be the greatest impact of the event on the city.  Pratt St., Light St., etc. have been overdue for repaving.