The Old Measures are a series of simple dances that appear to have formed a ritual beginning to Elizabethan and Stuart revels and dances.
For an overview of the Old Measures I can't do better than suggest Practise for Dauncinge: Some Almans and a Pavan, by Patri J. Pugliese & Joseph Casazza.
The dances are useful for modern re-enactors: they're attractive, enjoyable, easy to learn, suitable for people of varying physical ability, and they can be danced by many people at once.
My notes for each dance cover only the rough outline, and maybe keep a record of "local custom" - I've generally not attempted a discussion of reconstruction issues here, as the material is so well covered by others.
For further information see:
And of course numerous other books and articles.