Forza Motorsport 4 is adding another 10 cars this April, with the "Alpinestars" pack. It features a set of cars spanning from a 1959 Cadillac to a 2012 Jaguar. You can try them out, since there is almost no chance you'll ever be able to afford all of them in real life.
The pack includes the 2011 Mercedes Benz #35 Black Falcon SLS AMG GT3, 2011 Aston Martin #9 Aston Martin Racing AMR One, 2012 Jaguar XKR-S, 1995 BMW M5, 2011 Maserati Quattroporte Sport GT S, 1985 Maza RX-7 GSL-SE, 1972 Mercedes-Benz 300 SEL 6.3, 1959 Cadillac Eldorado Biarritz Convertible, 1997 Volvo 850 R, and 2012 Scion tC. Or, for those of us not fluent in makes and models, the pack includes a bunch of cool cars. It will hit on April 3 for $7 (560 MSP).