Q: How many vegans does it take to change a lightbulb ?
A: Two. One to change it and one to get out a copy of The Ethical Consumer and discover to his/her horror that the manufacturer (Thorn Lighting) is part of Thorn EMI who are involved in, errrr, I dunno, testing software on mainframes or making farms for 3rd world potaters or something.
A: Dozens and dozens to go round selling raffle tickets so they can afford to buy the new one.
A: Two, one to change it and one to phone round and cancel the party they were going to have to celebrate the old one burning brightly for 50 years.
A: None. They are all too busy on much more important projects, like organising each other's lifts to the veggie restaurant meal.

Q: How many VMS heads does it take to change a lightbulb ?
A: All of them, and they will all scream at you in unison and tell you that the only lightbulb you can use is a 100-watt soft white but you can use any 100-watt soft white as long as it's manufactured by DEC.
A: "Errr... Well, I've got a patch that I could apply to it, but if you can just wait till next year, it'll all be fixed when we upgrade to lightbulb version 6.1..."