Gonna be in Baltimore for 2 days.
It would help to be more specific. Are you looking for the ultimate crab cake? Interested in the Baltimore bar/food scene? Are you going to be here in the summer and want to try a sno(w)ball with marshmellow topping? Want the best of Baltimore pit beef? There are probably places you HAVE to check out in each of those categories that are unique to Charm City.
B'more neophyte here: Vaccaro's at Albemarle beats the 2xxx blocks of Steinway street in Astoria for Italian bakery.(not by much, but enough)
what's cool about Faidley's is while standing and slurping down the (cheap and plump!) oysters - not from the Bay sadly - shucker said Gulf, one can ponder the signs and consider what one might stew with the offered fresh muskrat.
not food, but call ahead to the medical examiners office for creepshow dioramas used in forensic training for the last 50 years not generally on public view - keep meaning to check that one out.
What type of cuisine or price range?
THe Charleston Goup is $$$ but alwaya are great dining experince:
http://www.thecharlestongrp.com/- 5 excellent restaurants to choose from
Petite louis is my favoriete french bistro.
LaFamiglia is a great italian place- http://lafamigliabaltimore.com/
Gertrudes at the TheBaltimore Museum of Art nice Maryalnd cuisine
tio pepe's- high end spanish
black olive- middle eastern/ mediteranean in fells point
obrycki's- maryland crab house
lexington market- walk the market and have a dozen oysters and a backfin lump crab cake at faidleys, a chocolate top cookie at Bergers bakery, an italian sausage at Pollack Johnnies, some fresh roasted peanuts out front some fresh Utz potato chips at the Utz stand and whatever else floats your boat during your grazing. go during the day not at night--closed and not safe at night
charlestown's- excellent in Fells Point area