Challenge Games, an Austin, TX-based online gamer, has raised a $4.5 million first round led by Sequoia Capital. The company’s games include fantasy game Duels, and the newly launched Baseball Boss. The browser-based online baseball game combines gameplay, along with an MLB-approved online trading card aspect. The cards of real players going back to 1907 are used to build teams. The company touts the fact that its games are multi-player and short, but also asynchronous (like the uber-addictive Scrabulous). CEO Andrew Busy previously co-founded Pluck, which was sold to Demand Media.