Three days in Edinburgh...what to do???

Castle
Holyrood Palace
Bus Tour
Walk whole of Royal Mile from Castle to Holyrood stopping off at Gladston's Land and Tron Kirk
Climb Scott Monument
Walk up Calton Hill at East end of Princes Street
Ghost Tour
Magdalen Chapel in the Cowgate.

All these are within a 1 mile radius. Edinburgh's a walking city.

.Try the Hop 0n Hop off bus, very amusing commentary
Just wandering among the old shops is fun enough.
The tourist info shop is the place to start

the castle tour is really interesting

1) The Bible doesn't say that Jesus was crucified on Friday. That is a calculation based on the traditional date of the crucifixion. So even if the expression is wrong, it isn't (technically) a Biblical error. 2) "A day and a night" was a Hebrew idiom for any part of a 24 hour day. You can actually read detailed descriptions of this idiom in the Talmud. What we would call "a day and a half" was called "two days and two nights" in Hebrew. Of course, the Hebrew linguistic structure makes the expression sound more natural...

Attend a few boring lectures at the Joseph Black Building, Department of Chemistry, University of Edinburgh?

jk jk =p

You might as well go see the castle.

Edit: Here are loads of other things to do -

http://www.edinburgh.org/events/
http://travel.yahoo.com/p-travelguide-2795341-edinburgh_things_to_do-i