Brainfuck, but with parentheses only.

>    )))
<    (((
+    ())
-    (()
.    ()(
,    )()
[    )((
]    ))(

Hello world example:

()))(((()(())))(())(())))))()))))(()
(()(()(()(()(((((())(((((()(()((((()
(()(()))()))(()()()))))))))())()()))
)))()(()(())())()))((()()))))(((((((
((((((()(())())())()((()(()(()(()(()
(()()((((((((()()())))))))))))())()(