A little romantic waterfall in a nostalgic color palette. In other words: Random ASCII blocks scrolling down. Not exactly 140 bytes in utf-8, but still 140 characters (Twitter accepts it).
C=" ▒▓█\n";J=[4];w=50;setInterval('O=0;for(K=w*w;K>w;J[1+K%w]=Math.random()*4|0)O=(C[J[K]=J[--K-w]])+O;document.body.innerHTML="<pre>"+O',w)
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