Tomorrow we're going to my uncle's place for dinner.
Tips
culture
Chinese family terms are precise about which side of the family someone is on. 姨父 = mother's sister's husband; 舅舅 = mother's brother; 叔叔/伯伯 = father's younger/elder brother; 姑父 = father's sister's husband. English collapses all four into 'uncle'.
mistakes
Don't confuse 姨父 (yífu, with neutral tone on 父) with 姨夫 (yífu, same pronunciation, alternative writing). Both are accepted; mainland mainstream usage prefers 姨父.