It's a new week and that means it's time to check the most interesting insider purchases from the last week. After checking through numerous filings using insider tracking tool Form 4 Oracle, here are my top five from the last seven days:

Company

Closing price 8/22/05

52-week change

Align Technology (NASDAQ:ALGN)

$6.53

-56%

Chesapeake Energy (NYSE:CHK)

$27.29

+97%

eResearch Technology (NASDAQ:ERES)

$15.77

-21%

Midway Games (NYSE:MWY)

$16.00

+34%

Rockwood Holdings (NYSE:ROC)

$20.25

+2%



Sources: Fool.com, Yahoo! Finance

All of these stocks have an interesting story with respect to insiders, of course. Some are just more interesting than others. Take Chesapeake Energy CEO Aubrey McClendon, for example. According to Form 4 Oracle, he's spent close to $10 million on stock in the Oklahoma-based utility since late last week. And he's been buying since last January. Now take a look at the 52-week return for his company's stock. Not bad, eh?

Also of note is the buying by former Cleveland Cavaliers owner Gordon Gund in Align Technology, which is trying to revolutionize orthodontics. Gund, his investment firm, and trusts for his family have been buying shares for more than a year now, with little to show for it in terms of returns. But Gund has a track record as a successful investor. For example, he sold his stake in the Cavs for $375 million, an 18-bagger over his initial $20 million investment, according to news reports. His continued faith makes me wonder if this company belongs in our Rule Breaker Universe (click here to access it directly, or take a risk-free trial).

That's it for this week. See you back here next week, when we dig through more insider deals in search of the next home run stock.

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Fool contributor Tim Beyers usually favors two scoops of ice cream over the inside scoop. Tim didn't own shares in any of the companies mentioned in this story at the time of publication. You can find out what's in his portfolio by checking Tim's Fool profile, which is here. The Motley Fool has an ironclad disclosure policy.