http://www.mediafire.com/download/20u6az661n2dr1d/Obby.zip

That's a singleplayer world with an example built (i have tested it on civcraft too of course). It must be North/South I think.

Script:

$${do(800);look(70,300);wait(200ms);key(use);wait(400ms);slotclick(0,LMB,shift);wait(200ms);slotclick(82,LMB);wait(200ms);gui();wait(100ms);do(10);for(#i,0,1);if(#i=0);look(0,1);else;look(180,1);endif;wait(200ms);slot(2);wait(200ms);do(3);key(use);wait(100ms);loop;look(80,345);wait(200ms); key(use);wait(200ms);look(320,50);wait(200ms);key(use);wait(200ms);if(#i=0);look(180,355);else; look(0,355);endif;wait(100ms);slot(1);do(210);key(attack);loop;next;loop;loop;}$$

Get rid of line breaks and just paste that into a macro key (you can break it down into a list of commands and use a file too if you're used to that). To use:

1) Start with the South side full of obby with the pistons retracted, and the north side pistons closed and clean, like it is in the save file.

2) fill the top chest with string and make sure a stack has filtered down to the one below it. The one below must be filled in the rest of its slots with cobble or whatever except the first slot. The top chest could for example get continuous input from a spider grinder, or could just be linked to 7 other DCs or what have you.

3) put a pick in your leftmost hotbar slot and make sure slot 2 is empty.

4) Stand right in the middle of the line between the two half slabs inside

5) hit your macro key.

6) To stop it, wait until it's in the middle of mining to be safest, click on your client right in the middle so it doesn't swing aroud and mine your machine apart, hit ~ (i think is the default) and uncheck the macro from running. And make sure it's south side filled again, etc. before running the macro again.

The bottom chests could also be hoppered underneath to a larger amount of storage space.

To adjust for TPS, look toward the end of the macro where it says do(210); make that number higher or lower until it reliably mines through 3 obby at whatever tps it is. 210 is for somewhat low tps.

If you run it too quickly you'll get a lot of cobble - it makes cobble instead of obby if items are still sitting on top of the hoppers when lava comes down. If you slow it down, it won't do this as much. I'm sure there's some other way to stop this but haven't figured one out yet.

Also, somebody told me:

If you replace the hoppers with half slabs, then below the half slabs you place hopper minecarts, the obsidian will be grabbed by the hopper minecarts much quicker than normal hoppers. This reduces the amount of drops left on the hoppers which in turn reduces the amount of cobblestone generated from it.