Unexpected Cash, How to split

Unexpected cash is coming our way.  Its not enough to pay off the house or the mortgage, etc..  

I was thinking I should split it evenly with MB, and remove it from the checking account so it doesn't get used up for regular stuff.  Problem is this:  We are in the midst of a change with Luke.  MB is planning to go back part time, but that'll mean a pretty big hit to our income this year.  I have a friend getting married in Sonoma later this year, two family trips in the summer, and my sister's wedding in DC in December.