It was my usual habit to put on my lipgloss, let it settle while I put on the rest of my makeup, then apply lipstick. I have very dry lips so putting on lipgloss first will create a smooth base for the lipstick to glide on. Last Sunday, I wore MAC lipglass and we all knew how sticky their lipglasses were. I did not wait for it to settle and applied MAC Dressmaker Dressmaker lipstick straightaway and this was what happened. 
Ouch, this post could be renamed 'How to fix a broken heart'.
Step 1: Heat the stub to melt the product.
Note: Make sure the product in the stub is soft and creamy.
Step 2: Stick the top part of the lipstick onto the base.
Note: Press it down really hard so that there will be messy bits on the broken part.
Step 3: Clean and neaten with a Q-tip.
Step 4: Cool the lipstick in the fridge for about an hour or two.
Done!
I heated the stub over a hot water bottle. You can use other heating elements like hairdryer. Anyway, the idea is to melt the stub to a glue like consistency and stick the broken part onto it. It is very important to press the two parts firmly together so that they will become 'glued' as a lipstick when cooled. Don't worry about being messy because you can clean and neaten it with a Q-tip thereafter.
lucky you were able to save it 
genius! i have broke my MAC Hue once and i depot it into a 5g container.
will try this the next time, but of course im not hoping for any of them to break. hehe ^^
thanks the tip! sweet!