Implement heap snapshotting
Many javascript engines allow you to dump a heap snapshot in order to debug memory issues with external tools. We should have the same for Haskell.
Now we have @DanielG's generalised heap traversal it should be fairly straightforward to dump the structure of the heap out to a file in a specific format.
Ultimately I want someone to implement something like BLeak (http://plasma-umass.org/BLeak/) for Haskell.