The last cool date of April (only the third one in the whole month!) is today.  A halfback day – 4/26/15.  Start at 4 and go up 22 to 26 then come half way back to 15.

The first day of May is very cool!  Leave the zero off the front of the month and day and you have 5/1/15.  Leave out the dividing slashes to get 5115 – a Pallindrome!