Anne Robinson is another of the show's guests technically in Room 101 - although in this case Robinson was consigned to the room in a series later than the one she appeared in.
Ian Hislop put himself in Room 101 in the final episode. This was the only way to get Merton to agree to put himself into the room.
The most frequently nominated item to go into Room 101 is the sport of football, which has been nominated three times. Perhaps surprisingly, the person to first nominate the item was Nick Hancock, well known as a supporter of Stoke City. It did not go into Room 101.
Paul Merton once granted the once-in-a-lifetime experience of pulling the lever which cast items into Room 101 (the item was once-in-a-lifetime experiences). Merton claimed that no-one else except himself had pulled the lever before.