sacrilegious, you say? i agree. which is why i wanted a cup holder that is temporary and easily removed/stored.
i searched high and low and finally stumbled on what i think is the perfect solution (and with a total cost of only $5.99).
without further ado, here it is:

it's a Babies-R-Us stroller cup holder with a rotating swivel thingy (i know, it's a technical term). a knob on the outside loosens or tightens the clip. when needed, it can easily be clipped on to the map pocket and will hold a beverage securely in place for the return trip home.