I should probably have prefaced this post with the fact that I'm developer, not a dba.

I'm not sure what you mean by heaps. Do you mean like in memory tables? Such as DECLARE @tbl TABLE (...)? If so then yes but not anything since this started happening.

Friday the database was 4 GB, Monday it was 17+.

The only thing new in the database besides our routine stuff is the dba_spaceused proc and a view. Could a view (non-indexed) cause ridiculous growth overnight?

If there is really that much data in the database, then how do I find it?