Ooh yes I know exactly what you mean...Have 2 and 3yr old here, no garden or tele and struggle to keep them entertained and keep the flat under control
Play doh gets used a lot in our house too! They are really into making playdoh cupcakes, decorated with lots of glittery sprinkles and flags made out of cocktail sticks (Poundland, love it).
We sometimes make little oceans with bowls, water and some blue food colouring and make all the plastic animals go for a swim
Actually I love day baths! I tried that thing where you mix cheap shaving foam with food colouring and let them paint the bath and they loved that
We have a lot of discos (can you get fun kids radio station where you are?) and turn the sofa into a stage to dance on
We make lots of slides out of mattresses and make forts and dens with clothes horses and blankets, give them a torch each and it seems to keep them entertained for hours
We concentrated all our toys into being either duplo or trains so there was enough of each not to have fights (barely works but gives me 15 minutes peace on a good day)
Also made fishing rods out of sticks and magnets on a bit of string, chucked a load of metal things down the back of the bed and enlisted some 'helpers' to retrieve them
When I'm feeling strong they 'help' me with the chores like the washing, cooking and cleaning, which they love and I secretly despair at the total chaos! 