According to TFL's website, on the Underground this weekend no less than eight lines were either at least partially suspended or completely closed, leaving only three lines with a fully running, non-interrupted service. Those tourists eager to visit Camden Town and those dreadful, never-ending shops selling “I Went to London and Got Ripped Off for this Crap T-Shirt” or somesuch would have been perturbed to find that the Camden Town station wasn’t in action at all this weekend. The result must have led to Mornington Crescent station nearby resembling the gates of Hades. Likewise Brick Lane, now a tourist mecca and affected by the Circle Line (even if other lines serve Liverpool Street, and Aldgate East and Bethnal Green stations are relatively nearby).
There’s no doubt that modernising needs to take place on the oldest system in the world, given that the Underground infrastructure appears to be as riddled with holes as French Gruyère cheese. But when it does so, it means that people are forking out money to use a non-existent service. The Bus Replacement Services may be fine for travelling short distances; but long ones can be excruciating experiences, involving much gnashing of teeth and mounting feelings of dread as said bus trundles through never-ending weekend traffic, your eventual destination ever further off.
Yet at the same time, we endure tube fairs rising, which makes a mockery of the idea that the most expensive transport system in the world* should only charge what it does if it’s able to provide an equitable and appropriate service. And with only two years to go towards the Olympics, the prolonged closure of the Victoria line every other weekend means that visitors will find it difficult to see other parts of the city when 2012 rolls on - this on top of all the other line's closures.

*yes I know that link is three years out of date, but it still stands as far as I know...