Editor's note: In this feature from Stockpickr, we highlight lists of stocks that have made new highs, lows or seen other unusual activity.

52-Week Highs: Priceline.com ( PCLN) vaulted 22% Wednesday after the online travel company posted second-quarter earnings that shattered expectations. The company posted adjusted earnings of $47.3 million, or $1.11 a share, on revenue of $355.9 million. Analysts expected earnings of 89 cents a share on revenue of $354.3 million. The stock jumped $14.47 to a 52-week high at $79.56.

Rising on Unusual Volume: Priceline.com's ascent was on the back of volume more than seven times its three-month average.

Biggest % Gainers: Impac Mortgage Holdings ( IMH) surged 47% after reassuring investors it has enough capital to satisfy future margin calls. The stock had plummeted Tuesday, after a UBS analyst expressed doubt regarding whether Impac can meet margin calls. Wednesday the company made up for some lost ground, adding 57 cents at $1.79.

Biggest % Losers: Heelys ( HLYS) plunged 48% after the maker of wheeled sneakers posted impressive second-quarter results but said third-quarter results would be disappointing. The company earned $12.8 million, or 45 cents a share, on revenue of $74.3 million. Looking ahead, Heelys sees third-quarter earnings of 28 cents to 30 cents a share on revenue of $55 million to $58 million. Shares closed down $10.57 to $11.42.

52-Week Lows: Heelys sunk to a 52-week low.

Stocks with Unusual Option Activity: Medarex ( MEDX) was experiencing unusual option activity Wednesday. The biopharmaceutical company closed up $1.40, or 8.9%, to $17.01.

Latest Activist Situations: In a filing with the Securities and Exchange Commission, HealthCor Management disclosed a 9.01% stake in Trimeris ( TRMS) and noted it is interested in having discussions with the company's management concerning various strategies for maximizing shareholder value. The firm said they have requested a meeting with the company's management. The company closed up 63 cents Wednesday, or 10.8%, to $6.42.

Forum of the Day

Synaptics ( SYNA) reports earnings after Thursday's close, HazyDavy notes. Thoughts?

Do You Know the Answer?

What tech stock is best to buy at this point in time, korenidan87 asks.

Feeling Lucky?

And finally, try picking a random portfolio suited to do-it-yourselfers with more detailed analysis at I'm Feeling Lucky.
Stockpickr is a wholly owned subsidiary of TheStreet.com.