In "Fitzsimons on Rugby", Peter Fitzsimons lists his World XV of celebs that actually played (great book, by the way). This link gave me an excuse to drag the book out, and so for you reading pleasure the XV is, with a little summary of their playing experience and some anectodes:
1. Meatloaf (played US college rugby, as he confirmed to Fitz in person when they were on an Australian talkback show together with Nick Farr-Jones - who he knew. "looks like a prop should... great on long bus trips").
2. Charlie Chaplin (Played at school in England.)
3. Idi Amin (Represented Uganda in 1956. Also Ugandan heavy weight boxing champ.)
4. Bill Clinton (Oxford Second XV secondrower. "By god he'd be a good man to go on tour with!")
5. Malcolm Fraser (former Australian Prime Minister. Played for his boarding school in Sydney.)
6. Pope John Paul II (Fitz says he is alleged to have played for Poland, but he couldn't get him on the line to confirm.)
7. Che Guevara (Played for San Isidro in Buenos Aires. Decided to forgo representing his country in favour of exporting revolution to Cuba. Also worked as a rugby journalist/match reporter for a while.)
8. Boris "Frankenstein" Karloff (Played in England, then became Founding President of the Southern Californian Rugby Union in 1935).
[love the backrow of the Pope, Che and Frankenstein...]
9. PG Wodehouse (Dulwich College, London. Also wrote match report for the school paper.)
10. JFK (unconfirmed. But "There is something of an unwritten law in rugby that the five-eighth has to be a good-looking bloke, with the aspect of one who has never had a glove laid on him, even after years of weaving his magical way through opposition defences.")
11. Kerry Packer (schoolboy experience, but his Grandfather won a cap for Scotland).
12. Richard Harris (in the fringes of Irish selection. Reported to British journalist Peter Jackson that he'd give up the lot - all his acting career etc - for one Irish cap).
13. Prince Edward (2nd XV, Jesus College, Cambrdige).
14. Jame Joyce (cf "Portrait of an Artist" - per Fitz, "No serious rugby team is complete without at least one whigeing wally out on the wing..."
15. Sir Edmund Hillary (token Kiwi. Played for Auckland Grammar School.)
Coach: Benito Mussolini (rugby nut, introduced rugby to Italy after seeing it in France in the 1920s, convinced it would go a long way to toughening up a population he wanted strong enough to restore the former glories of Rome. Pre-match speeches would be a highlight.)
Referee: Denis Thatcher (apparently was a ref - highpoint being a touch judge for a couple of Five Nations games shortly after WW2).