InfoSpace spiked 31 percent after the operator of online search engines said it would sell its online directory business to Idearc Inc. for $225 million.

Trading volume surged to almost 12 times its normal 100-day average Monday. Volume slowed through the week, and the stock kept most of its gains. Shares ended the week up 33 percent from its Sept. 14 close, finishing Friday at $17.68.

Factory Card & Party Outlet Corp. slid into the limelight Tuesday, and more than doubled its price on an almost 28 percent rise in volume, on news that AAH Holding Corp. is buying the party supply chain for about $56.1 million in cash, or $16.50 per share.

Shares hovered near the acquisition price through the week, and closed Friday at $16.24, from a Tuesday close of $8.05.

On the declining side, CarMax Inc. shares sank 15 percent Wednesday after the company missed analysts' expectations for sales in the second quarter and cut its profit target for the year.

Volume swelled to 7 times its usual level. Trading volume slowed but stayed higher than normal through the rest of the week.

Shares ended the week down 13 percent at $21.80, from a Tuesday close of $25.06.

Circuit City Stores Inc. shares dropped 18 percent Thursday after the electronics retailer said it lost $62.8 million in its fiscal second quarter on lower overall sales and continued restructuring activity. Trading volume jumped to about 7 times its usual level.

Friday, shares inched down a bit more after a Bear Stearns analyst downgraded the stock.

Shares changed hands about three times more than usual Friday, falling 19 percent from Wednesday's $10.57 price to end at $8.51.

Finally, Harman International shares gave up $23.49, or 21 percent, to $88.76 Friday on media rumors that buyers backed out of an $8 billion takeover of the audio equipment maker. The company confirmed the report after the closing bell.

Volume jumped to 31 times its normal level.