Sorry for stirring things up!

As far as I know the examples just show different ways of saying the same thing. The emphasis is slightly different.  I believe that they are pretty much interchangeable. Lets hope one of our experts reads this so that it can be verified.

I forgot your gift.  olvidé tu regalo,  me olvidé de tu regalo,  se me olvidó tu regalo

He/She forgot lunch.  olvidó el almuerzo,  se olvidó del almuerzo,  se le olvidó el almuerzo.

We forgot your birthday.  olvidamos su cumpleaños,  nos olvidamos de su cumpleaños,  se nos olvidó su cumpleaños

As said above, the different variations of "olvidar" have to do with emphatic stress (or focus, depending on what kind of linguist you're talking to). 

Now listen, I don't want to discourage any of your great analysis, but I do want to tell you that when it comes to tiny things like this difference in emphasis, it's better if you something you pick up on the fly; the analysis doesn't really make sense until you already know it. 

Trust me on this.  Here's a belabored analogy:  my driving teacher told us a thousand times to turn the wheel ALL THE WAY when parallel parking... but then when I was in the student driver car, I didn't do it, and so my angle was all messed up and I had to stop and try again.  It wasn't until then that I REALLY understood that you had to turn the wheel ALL THE WAY.  When he asked if I had been listening, I said something stupid like, "I heard you before, but I didn't really understand... until I already knew it."

Ok, back to the verb:  discuss, analyze, but I forbid you all to get frustrated about it; nobody's going to test you over it, it's too subtle to confuse anyone, and it's one of those things where, one day, you'll realize you already know it.  And then the analysis will make sense.

JP - You're totally right.  I am big on knowing and understanding why we do things, which usually makes remembering something a lot easier (when everything makes sense).  I need to apply it to learning Spanish. 

Thanks to you both :)

thanks for being so patient with us.  This is kind of a tough translation question. 

here's my final answer:

• Olvidé tu regalo. I forgot your gift.  This is the verb olvidar
  
• Me olvidé de tu regalo.  I forgot your gift. Same meaning, different verb:  olvidarse de. 
  
• Se me olvidó tu regalo.  I forgot your gift (the gift forgot itself to me).  Slight semantic difference:  the gift is now the subject and actor of the sentence.  "me" might be interpreted as the victim of the forgetting, rather than the agent of the forgetting.   This is the one you might us with the tone of "it all happened so fast," like it was an accident, like it was nobody's fault.

Again, this distinction is tiny, and native speakers won't expect this level of precision from you until you're very advanced; until then, they'll let it slide.

Me parece que cada semana hay líos nuevos en mi trabajo.  Impresos nuevos para rellenar.  Reglas nuevas y locas que tenemos que seguir.  Todo además de mucho, mucho impresos y reglas viejos!  ¡Qué lío!

Que quiero decir:

I don't know why everything is in bold.  I'm going to go against the grain...

It seems to me that each week there are new hassles at my work.  New forms to fill out.  Crazy new rules we have to follow.  All in addition to many, many old forms and rules.

What a hassle!

¡La negrita no es voluntaria!

What's with all this writing in bold anyway?