Some quotes I like today are:

"A merry heart doeth good like a medicine"
"He that is of a merry heart hath a continual feast"
"A merry heart maketh a cheerful countenance: but by sorrow of the heart the spirit is broken."
(scriptures in the book of Proverbs.)

"And they sat down, and did eat and drink both of them together: for the damsel's father had said unto the man, Be content, I pray thee, and tarry all night, and let thine heart be merry."
Judges 19:6

"One of the best things you can have up your sleeve is a funny bone."
Author unknown