こんばんはみんな。

Today was not interesting.
今日がはおもしろいくないですよ。
I did a lot of homework...
私はたくさんの宿題をしました。。。（；＿；）
It wasn't fun -__-
楽しいくない。。。
Was everyone else's day interesting?
みんなさんの日をは面白いかった？

こんにちは（・∀・）

最近忙しいです＞＜

私も、今日は楽しくありませんでした。。。

Some general advice:

Online it is best to use こんにちは to say hello regardless of your time. Unless speaking to a person or people specifically through IM when you know the time they are reading it (one would assume as you are typing it). 

Refer to others, especially everyone「みんな」with an honorific. みんなさん would be how you want to politely refer to everyone. It can be considered rude to not do so.

Do not mix polite 「丁寧語」 and casual language 「くだけた」. Either end everything with です・ます etc. properly or state everything casually.