This, allegedly the world's largest transportable (in 24 lorries) observation wheel, was erected in the Square in October, remaining until the end of February. At 60 m, and 365 tonnes, with 50,000 lights, it's about half the height of the London Eye. Originally installed near the Champs Élysée, Paris for two years (one of the 42 carriages was designed for President Chirac), it was in Birmingham for christmas 2003.
Somehow £5 each for 20-30 mins on a cold, cloudy day seemed expensive; in hindsight I slightly regret that decision.