I switched back to Black version, and I flew to Nimbasa City to battle at the sport stadiums. I visited the Small Court first, but the field was blocked, so I had to access the other stadium instead. I battled a Gentleman-class trainer inside, and he rewarded me with tons of cash, which was awesome. I left to the Ferris wheel afterwards, and I battled the trainer that was there. I then headed over to Opelucid City, and I visited the Battle House. I participated in two rotation battles, then I went to Route 10 to capture a wild Vullaby. I flew to Undella Town after that, and I battled The Riches again. I managed to defeat them all, so I won't be able to battle them again anymore, but at least I got tons of experience points and cash from them. I saved at the Pokemon Center after the battles.