'Hana ni arashi' (flowers before the storm) - Bad things happen after times of great joy.
'Minoru hodo atama no sagaru inaho kana' (the ripe rice plant bows it's head). - This means 'maturity brings humility' I like this one for the imagery. Rice is such a big part of the Japanese diet and when it's mature the top of the plant gets heavy so it droops. It's like it's bowing its head which as I'm sure you'll know is a sign of respect and humility in Japan.
'Nakitsura ni hachi' (bees when you're crying). - When you're already sad, misfortune comes. (bummer).
'Hane wo nobasu' (to stretch your wings) - I'm sure you're as surprised as I was to hear that Japanese people all secretly have wings (?) but this expression means 'cut loose' or 'let your hair down'.
'Kumo wo tsukamu you' (like holding onto a cloud). - this expression is used when people have impossible dreams.
And my favourite;
'Baka wa shinanakya naoranai' (only death can cure a fool). I don't think this one requires any explaination.