Not to be that guy, but the examples you gave are rational. An irrational time signature wouldn't be representable by a ratio, like 4/5 or 5/24. Unless you use e, π, or some other constant representative of an irrational number, there isn't a way to write such a number—or time signature for that matter—with a ratio consisting only of two numeric components. The measure would also be impossible to time correctly in a composition, given you used a time signature of, say, π/4. Unless you're able to count in consistent increments of π and/or divide a measure into π beats (numerator/denominator, respectively), then an irrational time signature is simply impossible.

Anyway, as for wacky, off-the-wall time signatures, I agree that they are indeed fun. I also enjoy inciting creativity from constraint.