There are a few interesting questions about the nature of programs, and specifically about sets of programs, as represented by lambda calculus expressions. 1. How many programs have N terms? 2. How fast does the set of programs of length N grow? 3. How many programs of length N converge? 4. What is the longest-running convergent program of length N? 5. How fast does BB(N) grow? 6. What percentage of programs converge?