If the museum that you're staying near is the Museum of London, it's very walkable - the museum is about five minutes' walk from the Millenium Bridge, which crosses from St Pauls Cathedral to the Tate Modern gallery (near Southwark Bridge) - go over the bridge, head towards the National Theatre, and just keep walking.

http://www.southbanklondon.com/

It's not far, but you better take the tube to Waterloo and start walking on from there. Once you get to the station, follow the directions and get near to where the Royal Festival Hall is, then walk along the river past Waterloo Bridge and towards the Oxo Tower, The National Theatre and Tate Modern. When the weather is nice (fingers crossed), it's nice to cross over the Millenium Bridge as there are some great buildings on that side of the river bank. Outside the National Theatre there's the regular summertime 'Watch This Space' festival that finishes at around 11pm on weekends (I can pm you the program, if you like), and inside the theatre there is a nice bar that faces onto the river and where you get a great view of Somerset House from its balcony.

shucks, i was gonna start a similar thread about what to do in LAX for 4 hours...ah well...all the good threads are taken.

Stay in the hostel, of course.

if its an international flight that gets in at 8 30 and then leaves at 1 30 the next day.. you wont be home to the hostel before 11 or so.. and you'll have to leave the hostel at like 10 am to get to the airport in time to check in and all..

so really that isnt much time haha.

I'd say get up really early and go to the museum and the science musem and tate gallery. I think they're all close by, the tate might be in a different spot. I cant remeber. but that would be really nice. I think.

i dont know if two of these things would still be there.. the trees one was an exhibition i think so wouldve moved on.. and the flat brass instrument one hanging from the roof well im not sure. but the crazy big glass thing.. i thin kthat was permanent. anyway.. there would still be lots of cool stuff.

my trip to the museum:

so i'm leaving in two days. i think i'll see what time i get to the hostel and if its not too last i'll walk to the southbank. then in the morning i'll walk around near the museum and then at around ten start heading back to the airport.
any good pubs in the area that i should check out?
once again, much obliged...