It's much more natural to say, 'Do you want to meet up for a drink sometime? ' than, for example, 'Do you want to meet up for a drink tomorrow? '
说‘Do you want to meet up for a drink sometime?’(什么时候见面喝一杯怎么样呢?)比起说‘Do you want to meet up for a drink tomorrow?’(明天见面喝一杯怎么样呢?)要自然得多。