DID YOU KNOW that walking around central london really doesnt take /that/ much longer than standing around waiting for buses and tubes?
well, on a nice day, having lost your oyster card really isnt the end of the world.
yesterday i walked from home in kennington to work in borough (15 minutes if i take the tube, 20 minutes if i walk), then walked to waterloo (10 minutes if i take the tube, 20 minutes by foot) for beirut, then walked to soho to do some drinking (about 25 minutes walk or 12 or so on tube) then to covent garden (18 minutes vs about 10)
covent garden back to kennington was a bit long - about 30 minutes walk for what would have been 15 minutes on the tube, i think.
anyway, its rather liberating, at least when the weather is ok, and its healthy n ting. i recommend it like some kind of guy that recommends stuff. roger ebert.