R

Raincheck:
An offer or deal that is declined right now but willing to accept later.

Raining Cats and Dogs:
A very loud and noisy rain storm.

Ring Fencing:
Separated usual judgement to guarantee protection, especially project funds.

Rise and Shine:
Time to get out of bed and get ready for work/school.

RomeWas Not Built In One Day:
If you want something to be completely properly, then its going to take time.

Rule Of Thumb:
A rough estimate.

Run out of steam:
To be completely out of energy

Bruce Larkin