Data ages like wine. Code ages like fish.

Fish can age well, there are some good aged fish sauces used in Japanese cuisine.

Milk also ages well (cheese).

Some subatomic particles might be a good choice. Pions decay in a few nanoseconds (for + & - charged) or attoseconds (for neutral). But "ages like Π⁰ particles" just doesn't have a nice ring to it.

  > Fish can age well, there are some good aged fish sauces used in Japanese cuisine.

So that would be TeX, the odd exception.