Complex sentence: GBA video paks were the feature prize in Vol.183 of Nintendo power magezine's monthly sweepstakes in which 5 grand prize winners would get a GBA SP and 20 GBA video paks.
Split into simpler sentences: GBA video paks were the feature prize in Vol.183 of Nintendo power magezine's monthly sweepstakes. In which 5 grand prize winners would get a GBA SP and 20 GBA video paks.