I really like this one:

The past is history,
The future is a mystery,
But today is a gift which is why it is called the present
-Anonymous

Tuesday's one was this:

There is always music amongst the trees in the garden, but our hearts must
be very quiet to hear it.
-Minnie Aumonier

& Wednesday's:

Happiness is something that comes into our lives through a door we don't
remember opening.
-Anonymous

Ahh... nothing like a few philosophical quotes to get me into my zen mode...