Here is a video description of my question: http://screencast.com/t/ooMJWlZkSX

On my membership page, using the membership plug ( subscribe_index.html ) There is a IF/Then code to display details if the user has chosen a membership account, but if the user is a new registrant and has not chosen a membership type the space will be empty.  
There is what it looks like:
{if isset($current)}{block_decorator name='box' type='empty' addClass="ow_stdmargin tour_step1"}{text key='membership+membership'}: <span class="ow_remark ow_small">{if isset($currentTitle)}{$currentTitle}{if $current->recurring} ({text key='membership+recurring'}){/if}{/if}</span><br />{text key='membership+expires'}: <span class="ow_remark ow_small">{membership_format_date timestamp=$current->expirationStamp}</span>{/block_decorator}{/if}
How do I place a block of text if ($current) is empty or null, or simply a {else}.  I need to promote my trial, so if there is no membership type selected , then the default will be block of html that will promote the trial.  Everything Ive tried results in s 500 error.