Well in the UK you have a legal right to ride as a bicycle is defined in law as 'an aid to pedestrianism' - and you don't need a license to walk down a road either.
In the UK the tax disc is Vehicle Excise Duty. You don't have to pay on two counts:
1 It's not a vehicle (see above)
2 It would be in the zero emission tax band anyway.
ALSO (see I'm getting mad now) a bike does about 1000th of the damage to a road of a car (due to its low weight).
So if I paid the VED proportionate to my real wearing out of the road: damage (1/1000) and mileage (5,000pa compared to 10k for an average British car) then that makes me owe just over 9p.
For years it was law to buy a liscense in Los Angeles. You had to go to the police station, walk into the lobby, ask the desk sargent for a liscense. This was to aid in recovering stolen bikes. Just last year the city council voted to dispense with it not because nobody did it anymore, but because it was not politically correct to ask illegals to volutarily approach a police officer. The crazy thing is most illegals that ride bikes are riding stolen bikes, and LAPD has a hands off policy in response to profiling.
'90 Offroad "Proflex"
'97 Proflex 957 Large, '97 Proflex 957 Small
'99 K2 OzM, "98 Proflex 4500 frameset
'00 K2 3000, '00 K2 4000
'02 Serotta CSTi, '95 McMahon FS