Regular major events held on the Common include The May Day Fair, Strawberry Fair and an annual fireworks on Guy Fawkes Night, 5 November, which regularly attracts around 25,000 people e.g. in 2006. Other events include fun runs and cycling events where the common is used as a start / finish point. A vigil and lantern floating ceremony took place on the common on Hiroshima Memorial Day in 2006.
Cambridge Midsummer Fair was granted a charter by King John in 1211, and was originally held on or near the feast of St Etheldreda. Originally a trade fair, income from the event went to the Barnwell Priory. In the sixteenth century the council and Mayor of Cambridge acquired the rights for the midsummer fair, with University Proctors retaining the right to search the fair for beggars, vagabonds and lewd women. The latter right in particular was hotly disputed. In the 18th century was named the Pot fair due to the quantity of China traded there, and it was popular among gypsy travellers for trade in horse and cattle. In more recent times it has become a pleasure fair with amusements taking the place of trade in goods.
In March 2006 Geoffrey King, who later became the chairman of the Friends of Midsummer Common, put up £20 to investigate the possibility of introducing a "residents’ herd" of cows to the common, at a meeting of the Brunswick and North Kite Residents' Association.
On 7 April 2007, after a period of time during which there had been no cattle on the common for a number of years, a small number of Red Poll bullocks, owned by a Cambridge resident, were introduced to the common. The grazing of cattle on the common is controversial, given the other uses to which the common is put, which may conflict with grazing.