Make a word cloud from a text
Python 3, 363 308 293 274 characters

import os,sys,re,collections as C
c=C.Counter()
n=sys.argv[1]
o="graph d{"
for w in re.findall("\w*",open(n).read()):c[w]+=1
for w,x in c.most_common(75)[1:]:o+="%s[fontsize=%s,shape=none];"%(w,x/5)
open(n+'.dot','w').write(o+"}")
os.system("fdp -Tpng %s.dot&gt;%s.png"%(n,n))


Call it like this: python cloud.py file.txt. The script uses Graphviz's fdp force-directed graph generator to generate the image (it will spit out a GraphViz file to file.txt.dot and a PNG image file to file.txt.png). This means you'll need to have Graphviz installed.

The image above is the cloud it makes of Shakespeare's Hamlet - you can tell, since it contains "To be or not to be". There's also some delightful nonsense to be found: 


  It is, to You and I, the Ham of Not thatO lord have us, what now...