I have 2x Cambridge Bike tour tickets for sale that can be used this weekend Fri 31st - Sun 2nd inclusive. You can choose between the Granchester or City tour, both lasting around 2-3hours.
Please view their website for more details:
http://www.cambridgebiketours.co.uk/
I bought these vouchers but will not get time to use them, have used the company I purchased them from several times before, you simply give the code to the Cambridge Bike tour company (which I have). Tickets are normally £20 each!