http://regex.alf.nu/

=== Plain strings ===
<code>
foo (207 points)
</code>

=== Anchors ===
<code>
k$ (208 points)
</code>

=== Ranges ===
<code>
^[a-f]+$ (202 points)
</code>

=== Backrefs ===
<code>
(.{3}).*\1 (200 points)
</code>

=== Abba ===
<code>
^(?!.*(.)(.)\2\1) (193 points)
</code>

=== A man, a plan ===
<code>
^(.)(.).*?\2\1$ (175 points)
</code>

=== Prime ===
<code>
^(?!(..+)(\1)+$) (284 points)
</code>

=== Four ===
<code>
(.)(.(\1)){3} (197 points)
</code>

=== Order ===
<code>
^.{5}[^e]?$ (199 points)
</code>

=== Triples ===
<code>
^[378][12479]|00($|[369]|1[25])|55|2[347] (589 points)
</code>

=== Glob ===
<code>
ai|c$|^p|[bcnrw][bnopr] (397 points)
</code>

=== Balance ===
<code>
^(<(<(<(<(<(<<>>)*>)*>)*>)*>)*>)*$ (286 points)
</code>

=== Powers ===
<code>
^(x|(xx){1,9}|x{32}|(x{64})+)$ (80 points)
</code>

(I'm too lazy to deal with the following two)

=== Long count ===
<code>
0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 101.{6} 1101 1110 1111 (198 points)
</code>

=== Long count v2 ===
<code>
0.{9}10 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110.{4}1$ (197 points)
</code>