Splat (Simple Program Launching and Termination) allows you to launch multiple applications, Windows services, folders, URLs and more, on demand and according to the rules you specify.
You could use the program to launch a complete set of applications, for instance, maybe everything you need for a work task.
You might then have a gaming profile which closed all those programs, unnecessary Windows services and other tasks, freeing up resources before launching your game (optionally with a higher priority than usual).
It's just as easy to open groups of URLs, either alone or with other programs.
While you could do this with a batch file, Splat does give more control over timing: you're able to launch tasks immediately, after a number of seconds, or only when CPU usage falls below a particular amount.
You profiles don't have to blindly launch multiple instances of the same programs, either. There's an option to only launch your target app if it's not running already.
The program also offers exceptional choice of hotkeys, with you able to combine Ctrl/ Alt/ Shift/ Win modifiers, letters/ numbers/ function keys, multimedia keyboard buttons, even mouse actions (Ctrl+Alt+F1+Mouse wheel down, say).
The interface is a little unpolished, but the core functionality works well, and Splat is already a convenient way to open groups of applications on demand.
Splat makes it easy to launch or close multiple applications/ files/ folders/ URLs on demand. There are plenty of other ways to do something similar, but Splat's timing control and hotkey options help it stand out from the crowd. Give it a try.