At The Movies
Buy a theater advertisement or arrange for a local movie theater to play a video tape of you before the feature.  In it, tell her how much she means to you and ask if she'll marry you.  Be ready to drop to your knee (amid the popcorn and theater candy) and present the engagement ring..
 

Your Good Fortune
Steam a fortune cookie until it is soft enough to open.  Place the diamond ring inside with a note/fortune telling her you'll love her forever.
 

Beach Surprise
Take her for a long walk on the beach.  Have a friend prepare a special area set up with flowers, champagne, music and an engagement proposal written in the sand.
 

Love From Above
Go to the beach or another open place, hire a plane to fly over you with a banner of "I love you (bride's name), will you marry me?" and wait her reaction with the engagement ring in hand!
 

Running Down the Aisle
Have four of your friends sign up with you for a road race (i.e., a 3K, 5K, etc).  Tell your girlfriend to wait for you and cheer you all on at the finish line.  Have each person wear a shirt with one word on the front so that it spells out “name, will you marry me?”  Give her the ring as you cross the finish line.
 

The Masterpiece
Ask a local museum or art gallery if they would put your engagement ring on display with a display card reading that this was the very ring was used by you on that particular day to ask her to be your bride.  Or, write your proposal on parchment (with her name as the title), age the paper (using crackling agents, etc), frame it in an antique-looking frame and have the gallery hang the piece for viewing.  When she sees her name, she's sure to read it.  And then...be ready with the ring.
 

Treasure Hunt
Send her on a treasure hunt.  Give her clues that take her to places of sentimental value to you both.  Finish the hunt with a ring, roses, candlelight dinner and you.
 

Rolling Out The Red Carpet
Make a "carpet" of red rose petals from her front door to her bedroom.  On the bed, place the ring box inside a large heart made of rose petals.  Take her home after her work, and after she reaches the bedroom, propose to her.
 

Internet Proposal
Create a web site (i.e., a fake news site or spoof of popular search engines like Yahoo or Google) dedicated just to her.  Have the cover story or the late breaking news be your engagement proposal.
 

Billboard
Rent a billboard with your pictures and your proposal located along her normal commute route. 
 

Primetime Proposal
Have a commercial made on public access television.  Check see when the commercial will air, and as you channel surf with her, stop on your commercial and watch yourself propose.
 

Puppy Love
If she's a dog lover, go to the pet store or local animal rescue and find the cutest, cuddliest puppy they have.  Have a special dog tag created that says, "Marry Us."  When she arrives home from work, giver her the puppy and have the engagement ring hanging from the collar.
 

Fishing For Fiance
Take her fishing, but just before you arrive have a friend drop a few lines in the water.  Have your friend bait one of the hooks with the ring (in a plastic bag or other secure enclosure).  After fishing for a while, suggest that she check the lines that were already in the water.  Be ready to propose when she reels in the ring.
 

Three Strikes and You're In
Take her to a minor league baseball game and arrange to have her seat selected "at random" to throw out the first pitch.  While on her way to the field, slip away and change into the catcher's uniform and mask.  Have the team allow you to catch the first pitch.  Make her throw several pitches by indicating that each pitch is "no good."  Finally, call a meeting at the mound, remove the mask and propose to her.
 

In The News
Place an ad in her favorite magazine or newspaper with your photos next to it, so she is sure to notice. Imagine her surprise when she is reading and sees her face in her favorite magazine.
 

Frosty the Ring Bearer
If proposing during the winter, make a snowman together and while she's not looking, slip the ring onto the snowman's carrot nose or place the ring box in his hand.
 

"On Air" Proposal
Call her favorite local radio station and propose to her on air.