One day/night in Cologne - what to do?

Doing an exhibition with a colleague so have evening to relax

Less after cultural tips (cathedral etc) and more after things like the best bars - cool places to eat etc

This should be no problem at all. Believe it or not Cologne has more breweries than any other city in the world - and they all brew the local Bier, Koelsch! There are lots of Bier Halls in the old area of town around the cathedral, any of which would be a fun place to stop.

That's the thing to do, IMHO, in Cologne, if you want to get some of the local ambiance. Note that you will probably be located in the exhibit hall area, and need to take public transport to the main train station (Hauptbahnhof) which is located just next to the cathedral (it's actually rather impressive coming out of the train station). Cross over to the platz on the opposite side of the Cathedral from the train station, and you will be in the old town, you can just wander the streets from there to find a place - they are everywhere.

I'm not nuts about the Hard Rock Cafe idea. Why not do something local?

This is easy...Hard Rock Cafe, baby. There is a great hole in the wall Italian Restaurant a couple blocks up the hill from there...

EDIT: Actually Julie I agree with your local establishment idea..I just couldn't think of any names or addresses...like I know where "MY" Italian restaurant is but I just can't remember the exact name....It's you know "the italian restaurant we always go to" sort of thing...

A real cool place to eat is Tabula Rasa, Hansaring 131
50670 K枚ln. Their food is very original, freshly prepared, innovative, and I love the decoration. It's ok price-wise, not cheap, but not too expensive either. I used to go there with friends when we had a bit of an occasion to celebrate.