scrabble.py

from collections import defaultdict
from itertools import combinations

worddict = defaultdict(list)

letters='sillystring'

for word in file('/usr/share/dict/words'):
    w = word.strip().lower()
    worddict["".join(sorted(w))].append(w)

def find_words():
    for n in range(len(letters),0,-1):
        for p in combinations(letters, n):
            results = worddict["".join(sorted(p))]
            if results:
                return results

print find_words()