Take a particular size planetoid, thoroughly analyze it so we know its composion (there's another science mission right there), then attach a rocket to push it into Venus (we can learn how to manuever a big space rock to protect Earth from potential Earth-crossers and how to move them around for future mining purposes - two more missions).

The resulting surface impact debris can be shot into space, where a Stardust type ship (or ships) does a flyby to grab the material and return it to Earth.

Or we could have a waiting aerostat platform high in Venus' cloud deck if the impact won't quite kick enough surface material into space. We get another mission by having the aerostat explore the surrounding air deck while waiting for the debris to fly up and, presuming it survives - some of it has to to get the samples back to Earth, perhaps a really fast rocket that is initially shielded then dumps the shielding and zips off into space.

At first I was writing this tounge firmly in cheek, but now I am not entirely certain it is all that crazy.