Daytime..go visit national palace (fee 500bht), national museum (fee 200bht), wat pho (not remember the fee but cheaper than national museum) and last but not least wat arun (fee 100bht)..all of this place can be rich by taxi from silom (around 100bht fare) or the easiest way is by boat from saphan taksin bts station..so if you stay around silom,just take skytrain bts from sala daeng station..no need to hire any tour guide because they will reap you until bankrupt..
Night time..if you into muscular men so tawan bar at soi tharntawan is highly recomended..other than that you can visit jupiter(new and old),dream boys etc around soi twillight..forassage parlour,Arena at silom road is highly recomended..TQ