If someone wants a really world-class, high-value programming assignment, try making an Excel clone with no reachable limits on row counts, cell counts, worksheet counts, etc.
(If one exists already, I humbly eat crow now and request a link.)
Dunno about no reachable limits, but Quattro Pro will go up to a max of 18,278 columns, 1,000,000 rows, and 18,278 sheets, which is a bit more elbow room than you get in Excel.