Clojure

Need to use http but don't necessarily have a problem that warrants downloading the entire Apache HTTP client? Enter clj-http-lite which just uses the Java core libraries (but retains a sane interface).

A tuple library for small collections clj-tuple

Use complement to invert a predicate.

E.g. (complement string?)

Clabango is a Django templating port, that also seems to support filters and inheritance. Looks a bit less active than Selmer but its hard to see any differences between them currently.

Clojure templating frameworks: Fleet, Selmer and Stencil.

Fleet uses a special kind of limited syntax to interpolate what seems to be Clojure code into a template.

Selmer is inspired by Django's templating and is used in the Caribou framework.

Stencil is a fairly straight-forward Mustache port