Last week's

Investment Challenge

winner Russ Geissbuhler doesn't usually enter contests like this. But when he learned that the winner would get to spend a day in the trenches with

James Cramer

, he says there was no way he was going to pass up the opportunity.

Geissbuhler, who credits Cramer's wisdom for his mammoth gains last week, has embarked upon an aggressive strategy to seize the winner's crown.

The Eatonville, Wash., trader made more than $2 million last week after buying up a slew of

Dell

(DELL) - Get Report

call options for less than $1 each. When the price rose toward $3, prompted by the

Fed's

benign interest-rate hike and good news about the company, Geissbuhler cashed in.

"In real life, I would have invested a maximum of about 1% or 2% of our money in this type of trade," Geissbuhler explains, referring to the holdings he manages with his wife and partner, Melissa. "But second place doesn't go to New York with JJC."

Although he made a few other trades in last week's challenge, nothing came close to the gains from his Dell options.

And while he can only work on his fantasy portfolio a few hours each week due to his job as a full-time trader at home, Geissbuhler will undoubtedly remain a serious threat in the challenge.

He finished last week at $3,035,216, an increase of $2,697,771.

The other top five finishers for the week included David Betten, who ranked second at $2,116,629 with a $1,616,629 weekly gain. Betten moved up from fifth place

last week. Kent Hurd ranked third at $2,098,320 with a $1,598,320 weekly gain, after a fourth-place showing last week. Ivan Martinez ranked fourth at $1,738,945 with a $1,200,437 weekly gain, and Conrad Krol ranked fifth at $1,878,788 with a $1,045,307 weekly gain.

Registration for the challenge continues until 9 a.m. EDT Aug. 9.