Conditionals with normal order evaluation
Here is the church notation:

TRUE: $\lambda ab.a$

FALSE: $\lambda ab.b$

IF: $\lambda pxy.pxy$

By passing a church boolean as a predicate to the IF function, we choose one of two alternatives. TRUE chooses the first argument passed to it, and FALSE chooses the second.

We can derive COND by folding IF across a list of (condition, result) pairs

You can find wikipedia's explanation here, as well as assorted lambda calculus derivations here.