tknutsen,

This will find the right-most space (if a space is present) and return everything to the left of that space:
=IF(ISNUMBER(FIND(" ",A1)),TRIM(SUBSTITUTE(A1,TRIM(RIGHT(SUBSTITUTE(A1," ",REPT(" ",255)),255)),"")),A1)


@dgagnon, Your formula finds the left-most space and returns everything to the left of that.